This invention relates to a surface modifying process for synthetic polyester fiber products in the form of filament, fiber, woven fabric, knitted fabric and nonwoven fabric.
Because of their excellent physical properties, polyester fibers are recently utilized for a wide variety of purposes not only for manufacturing underwears and outerwears but also for making household goods such as bed sheets and carpets. Polyester fibers, however, are disadvantageous in that they have large hydrophobic properties and, when used in the form of wears, present only a limited sweat absorbing property and hence give a stuffy feeling. Also, polyester fibers easily absorb oily stains which, once absorbed, cannot be removed easily, and are readily charged with electricity so that they attract dusts and, when used in the form of wears, stick to the body while putting them on and, when used as a carpet, sometimes give an electric shock.
To eliminate these disadvantages, many methods have been proposed heretofore. One example is a method disclosed by McIntyre et al in the U.S. Pat. No. 3,416,952, wherein polyester fiber products are treated with a polyester polyether block copolymer prepared from terephthalic acid, alkylene glycol and polyalkylene glycol. However, a treating liquor containing such block copolymer is not stable against heat and, with a slightest temperature rise, the block copolymer which is being dispersed in the liquor starts aggregating. Accordingly, it is actually impracticable to treat the polyester fiber products properly with such liquor. On the other hand, although it is known that when a specific emulsifying agent or dispersing agent is added to said block copolymer the block copolymer dispersed liquor is stabilized, the fibers, even when they are dipped in a long bath (diluted solution having a large liquor ratio), cannot be modified enough due to the excessively low degree of exhaustion of said block copolymer into the fibers. Therefore such stabilized block copolymer is exclusively employed in only an ordinary pad dry cure process. This process, however, involves dangers that water spots are occured unless a rinsing and drying step is carried out after treatment and that the resulting treated fibers present treatment effects having a reduced durability. Thus, it has been intensively desired to simplify the process of the pad dry cure method and yet to improve the modifying effect.